This invention relates to a sewing machine control device for controlling the drive of a sewing machine, and more particularly to a sewing machine control device for displaying data to identify the direction of rotation and abnormal conditions of the sewing machine.
FIG. 1 is an explanatory diagram showing the entire arrangement of a conventional sewing machine control device. In FIG. 1, reference numeral 1 designates a sewing machine body; 2, an electric motor for driving the sewing machine 1; 3, a control device for controlling the operation of the motor 2; 4, a pedal for specifying a speed for the sewing machine; 5, a display unit for displaying abnormal conditions; and 6, a table on which the sewing machine body 1 is mounted.
The conventional sewing machine control device is arranged as described above. Depending on the amount of depression of the pedal, a rotation instruction signal is applied to the control device 3, whereupon the control device 3 applies a signal to the motor 2 which is based on the rotation instruction signal. As a result, the motor 2 is rotated to drive the sewing machine body.
When an abnormal condition occurs within the sewing machine body 1 or the control device 3 while the sewing machine body 1 and the motor 2 are being driven, an alarm is given with a warning signal displayed on the display unit 5.
The conventional display unit 5 is provided with several light emitting diodes (hereinafter referred to as "LEDs", when applicable) to identify abnormal conditions, or it is provided with a 7-segment LED numeric display panel to display digits to identify abnormal conditions.
Only when the sewing machine is rotated in the forward direction, the direction of rotation is displayed--when it is rotated in the reverse direction, the direction of rotation is not displayed.
With the conventional sewing machine control device, erroneously the sewing machine may be rotated continuously in the reverse direction to damage it, because it is impossible for the operator to determine with a glance whether the sewing machine is rotated in the forward direction or whether it is rotated in the reverse direction.
In the case where LEDs are employed to display the occurrences of abnormal conditions, different LEDs must be provided for different warning signals, and therefore it is necessary to increase the installation space for the display unit as much.
The same thing can be said about the case where a 7-segment LED panel is employed.
Thus, the display unit is unavoidably bulky, and accordingly high in manufacturing cost.